This invention relates to the bulk collection of strand, and in particular, to the bulk collection of texturized strand. A strand of glass filaments is typically formed by attenuating molten glass through a plurality of orifices in a bottom plate of a bushing. The filaments are attenuated by applying tensile forces to the streams of glass, so as to attenuate the streams. The filaments are coated with a sizing or binder material. The composition of the sizing material is tailored to the end use of the filaments. For example, if the filaments are to be used to reinforce an epoxy based composite then the sizing is formulated to be compatible with the particular epoxy. In this particular application, the sizing is tailored to provide the required lubricity, abrasion resistance, and integrity to the strand as it is processed in texturizing equipment while at the same time allowing for easy texturization of the strand in the texturization unit. The glass filaments are sized with the sizing material substantially immediately after they are formed. The filaments are gathered in parallel relationship to form a strand.
In conventional filament forming systems, the streams of glass have been attenuated by winding the filaments on an exterior of a rotating tube. The strand of filaments is wound on the tube as a cylindrical package. The winding device with the rotating tube pulls the filaments and collects the strand.
Instead of winding the strand around a rotating tube, the strand may be gathered into a container. The strand is typically collected in a container when it is attenuated by a pulling device such as mating wheels or a pair of belts. A bulk collection of strand can be easily shipped and used in subsequent processes.
Texturized strand is continuous strand that has been expanded or texturized. The fibers in the strand are separated to give the strand a full, wool-like appearance. Texturized strand dissipates air borne acoustic waves and also possesses good thermal insulative properties. Texturized strand is typically used in sound absorbers.
As the texturized strand is delivered into the box, excess air from the texturizing process tends to blow the strand around in the box during the filing process. This produces the conditions that result in tangles as the texturized strand is being pulled out of the box for subsequent processing.
Attempts have been made in the past to limit or eliminate the tangling problem. One such attempt is disclosed in U.S. Pat. No. 6,370,747 to Lewin et al. This patent discloses a method wherein texturized strand is directed into a four sided box with both the top and bottom of the box open. More specifically, the box is filled by directing the texturized strand down into the box though the open top. The bottom of the box opens into a screen covering a low air pressure chamber. The open bottom of the box allows the air to escape from the box quickly thereby significantly reducing the billowing of the strand in the box and, therefore, the formation of tangles when the strand is subsequently pulled from the box for processing.
Unfortunately, as the texturized strand or roving collects on the screen, the airflow resistance through the deposited strands increases. This results in less and less of the air being removed from the box by the low pressure chamber below the screen. Once the texturized strand or woven thickness on the screen exceeds about 10 to 15 centimeters (the thickness depends upon the pressure in the low pressure chamber), the amount of air removed from the box becomes so small that the strand is blown around in the box producing conditions that are known to cause strand tangling.
The current invention relates to a new and improved method and apparatus for eliminating the conditions that tend to cause the tangling of a texturized strand as it is removed from a box or container for further processing.